Whichever candidate one supports is their own business, and nobody should be attacked for it.
If Mike had posed with a pic of KKK Imperial Wizard David Duke when Duke ran for president (and took the additional step of proudly posting the pic on social media, had it existed back then), would this be an exception to the rule? You'd take issue with a person of color attacking Mike for posing with Duke? What if that person was Blondie?
Not trying to veer into sandbox territory, but just pointing out that some candidates are THAT divisive, and there's a reason why there's so much opposition to the very idea of the band playing for Trump. There's a reason why it's BAD for the brand. I'm not equating Duke and Trump, but I still would like to know your answer to the question.
In the hypothetical situation that Mike would've been photographed next to D. Duke, it's one thing to criticize his choice of candidate. I wouldn't have a problem with that. But, if one attacked Mike as a person, I would have a problem with it. And that's because you don't know why somebody chooses their candidate. Say, Duke had a specific policy that Mike agreed with that had nothing to do with his associate with the KKK.
Because Trump is a divisive candidate, I do think it would be a bad business decision to play his inauguration. Just as I think supporting Hillary is a bad business decision for other celebrities. More than any other election, this has easily been the most divisive and ugly. Why risk pi$$ing off half your fanbase?
Alice Cooper did it right. He performed "Elected" on Jimmy Kimmel on Halloween night, and skewed both candidates.